SECONDARY BATTERY HAVING IMPROVED LONG-TERM RELIABILITY AGAINST MOISTURE PENETRATION

摘要

Disclosed in the present invention is a secondary battery having improved long-term reliability against moisture penetration. A pouch-type secondary battery according to the present invention is characterized by comprising: an electrode assembly having an electrode lead attached thereto; and a pouch packing material which accommodates the electrode assembly such that a portion of the electrode lead may be outwardly exposed and which has a sealing portion formed along an edge thereof, wherein the sealing portion has a characteristic length of 10 to 19mm2/mm. According to the present invention, the characteristic length of the sealing portion of the pouch-type secondary battery is limited to a fixed range, thus limiting as much as possible a reduction in capacity of a secondary battery caused by the area occupied by the sealing portion while improving reliability against moisture penetration which might occur due to the long-term use of the secondary battery.